Endocrine disrupting compounds (EDCs) in the environment can cause a variety of physiological problems in animals and humans. Thus, measurement and analysis of EDCs in the environment is very important to the Environmental Protection Agency (EPA) in its Superfund monitoring activities. The investigators have developed a prototype macroarray that works exceptionally well with sheepshead minnow to predict estrogenic outcomes in laboratory-exposed fish. They seek to apply this technology to produce a macroarray membrane (or chip) for largemouth bass that would contain cDNAs for many of the major hormone receptors, many of their downstream-regulated genes and additional genes of toxicological importance. Gene arrays are powerful tools for identifying molecular changes in animals. Endocrine disrupting compounds act at the gene level to induce or repress gene expression through both receptor-mediated and non-receptor- mediated pathways. Based on preliminary data, the investigators expect to be able to identify gene expression patterns related to specific types of contaminants present in mixtures. They seek funding to prepare the arrays, test them under laboratory-exposed conditions and to test them at Superfund sites.